Politicians, scientists and environmentalists have turned up the heat on ministers and officials planning to merge the British Antarctic Survey (BAS) with an oceanography centre, before a meeting to decide its fate on Thursday.

"Only a few years ago prime minister David Cameron was photographed hugging huskies in the Arctic in an effort to stress his green credentials; I hope he can now reassure us that his government would not be so cynical as to refocus the UK's Arctic research on opening up the region to greater resource extraction," said Joan Walley, the Labour MP who chairs the environmental audit select committee. The proposed merger should be abandoned, Walley wrote on Wednesday in a letter to a parliamentary inquiry into the issue.

Four of the UK's biggest green NGOs – Greenpeace, the RSPB, WWF-UK and Friends of the Earth – also signalled their strong opposition to the merger. "Those who want to dismantle this leading scientific centre should hang their heads in shame. It is a grave mistake to take apart BAS when it is needed now more than ever," said Vicky Wyatt, Greenpeace arctic campaigner. "Politicians should be working to help our scientists understand and look after these areas, which are under threat from the effects of climate change, not rush through daft plans to undermine them."

The NGOs wrote to Prof Duncan Wingham, chief executive of the Natural Environment Research Council (NERC), which runs BAS and will decide BAS's fate on Thursday. The decision was to have been taken in December but was brought forward. That forced MPs on the commons science and technology select committee, which is investigating the issue, to call Wingham before them on Wednesday, along with David Willetts, the minister for universities and science. Willetts wants a 10% cut in NERC expenditure and a 45% reduction in its capital spending by 2015. Polar research, which is costly, has been chosen to take a major hit.

The planned BAS merger has prompted widespread outrage, with the former US vice-president Al Gore defending BAS as a "globally significant institution". The Tory MP Andrew Rosindell, chairman of the polar regions cross-party parliamentary group said the proposal was "utterly foolish", while Jonathan Shanklin, one of the scientists who discovered the ozone hole in 1985, said: "BAS is almost synonymous with the Antarctic ozone hole. Losing it would create a comparable hole in British science."

NERC's merger consultation document stated: "The oceans and the polar regions (particularly the Arctic) are 'frontier' environments where, of necessity, there will be increasing economic activity in the coming decades – not least because of increasing pressures on natural resources … A long-term vision is needed … to equip UK business and UK investors with the edge needed for de-risking major investment decisions in hostile, unfamiliar environments."

Wingham said previously that all scientific institutes were under pressure to provide value to the UK economy. But he denied that a more business-focused approach meant the council necessarily supported drilling in the Arctic, although he said future work would provide relevant information to oil companies.